Analyzing regional identity construction in the peripheral northwestern Costa Rican province of Guanacaste, and the creation of regionalist discourse and political organization in Costa Rica from the early twentieth century to 1939, this dissertation studies the historical dynamics between region and nation. The concept of region employed here is not focused on an economic, geographical, or historical entity but understood primarily as a space and a community imagined by the promoters of regionalism and by the intellectuals and politicians of the country's administrative center. The primary sources used in the dissertation are mainly government documents and newspapers. The principal vehicle in the creation of the imagined region and regional identity was the regionalist newspaper, which became the organ of the regionalist movement and the political party. The discourse of regionalist publicists emphasized harmony, unity, and class conciliation in the province, a construction that served to mask the conflictive social relations in the region and thus benefited the interests of the regional elites. Political regionalism in the form of a regionalist party that competed in national elections had a brief heyday in the late 1930s, but did not endure, as the Costa Rican political system made the transition from a liberal to a reformist/welfare state model beginning in the 1940s.